The Beta-adrenergic receptor-adenylate cyclase system consists of at least three separate integral membrane proteins, the Beta-adrenergic receptor, regulatory protein and catalytic protein. Regulatory protein binds GTP and synthesis. Few studies have examined the control of these proteins and their individual functions during the development of the catecholamine response. In my previous work, the Beta-adrenergic receptor-adenylate cyclase was characterized in developing skeletal muscle. In acord with the high capacity of eight-week skeletal muscle for glycogenolysis, adenylate cyclase activity increased 6- to 9-fold for sodium fluoride, guanylyl nucleotide and catecholamine activation compared to neonatal muscle. The number and affinity of Beta-adrenergic receptors, however, was unchanged. Is guanylyl nucleotide action and/or regulatory protein function modified to enhance the expression of adenylate cyclase activity in developing sarcolemma? to test this general hypothesis key features of guanylyl nucleotides/regulatory protein will be characterized in neonatal and eight-week skeletal muscle sarcolema. The effect of guanylyl nucleotides on the Beta-adrenergic receptor will be determined by measuring alterations in agonist binding affinity. Cholera toxin catalyzed ADP ribosylation will be performed to ascertain levels of regulatory protein. Catecholamine hormone stimulated GTPase activity will be measured by determining the release of (32P) for (Gamma-32P)-GTP to indicate the operation of the termination mechanism for guanylyl nucleotide effects. Complementation studies employing Lubrol PX solubilized regulatory protein will be performed to attempt (a) reconstitution of neonatal sarcolemma adenylate cyclase activity and (b) characterization of Mn++ ion dependent catalytic protein function. The results of this study should provide new and important information on the assembly of the Beta-adrenergic receptor-adenylate cyclase system during the development of skeletal muscle. The similarities between normal muscle development and the loss of catecholamine responsiveness in muscle disease may ultimately provide useful guides for defining the lesion in catecholamine hormone control of carbohydrate metabolism in diverse muscle disorders.